74 GUIDE TO THE FOSSIL REPTILES, AMPHIBIANS, FISHES. 
Wall-ease ancestral saw-fish; while teeth and pieces of the saw of 
3. Pristis itself occur in Eocene deposits (Table-case 7). The 
Table-cases 
Fig. 74.—Mandible of Ptychodus decurrens, from the Lower Chalk of 
Sussex; reduced. (After A. S. Woodward. Table-case 8.) 
Squatinidae and Rhinobatibae date back even to the Upper 
Fig. 75.—Skin-tubercle of the ex¬ 
isting Thornback (Baja cla- 
vata ), outer view and side-view, 
showing the prickle ; about 
nat. size. (Fossil in Red Crag, 
Table-case 7.) 
able skeletons of Cyclcibatis 
Jurassic ; and well-preserved 
skeletons are exhibited both 
from the Bavarian and French 
Lithographic Stone, and from 
the Upper Cretaceous of Mount 
Lebanon (Wall-case 3, Table- 
case 7). The large skeletons 
of Bhinobatus bugesiacus (Fig. 
73) and Squatina acanthoderma , 
mounted between Wall-cases 2, 
3 and 3, 4, are especially note¬ 
worthy as beautifully preserved 
fossil fishes. Some of the Raji- 
dae and Trygonidae are Upper 
Cretaceous, and the remark- 
from Mount Lebanon, in Table- 
